Another review suggested that the engine performance using RCO biodiesel and its blends was only marginally poorer compared to fossil diesel while NOx emissions were slightly higher while un-burnthy drocarbon emissions were lower (Enweremadu and Rutto, 2010).However, tests using 30% and 70% blends of biodiesel resulted in a sharp decrease in both smoke or soot and particulate matter emissions as biodiesel concentration was increased, average particle size was also reduced with biodiesel concentration, but no significant increase was found in the range of the smallest particles(Lapuerta et al., 2008; Ismail et al., 2013).